Light intensity control for railway signal lamps



Aug. 9, 1949. R. R. KEMMERER LIGHT INTENSITY CONTROL FOR RAILWAY SIGNALLAMPS Filed Dec. 10, I947 INVENTOR. lph jlfemnaerer HIS ATTORNEY NifiQmukm Patented Aug. 9, 1949 LIGHT INTENSITY CONTROL FOR RAILWAY SIGNALLAMPS Ralph R. Kemmerer, Swissvale, Pa., assignor to The Union Switch &Signal Company, Swissvale, Pa., a corporation of PennsylvaniaApplication December 10, 1947, Serial No. 790,901

6 Claims. 1

My invention relates to control of the light intensity of railway signallamps, and particularly to an arrangement for controlling railway signallamps to burn at times at a given intensity, and to burn at other timesat a given reduced intensity.

In railway signal systems, it is essential, for sake of visibility, thatsignal lamps burn at a given intensity during the daytime, whereas areduced intensity of the light from signal lamps is sufiicient at night,and may even be preferable because too great intensity of the signallights at night may cause discomfort to the enginemen. Furthermore, asaving in electric power is effected by burning the signal lamps at alower intensity at night. Then, too, in event of war, dimout control ofrailway signal lamps may be required for reducing their light intensityso that they will be less conspicuous, particularly from the air.

One feature of my invention is the provision of novel and improved meansfor at times lighting signal lamps by alternating current at a givenvoltage, and for at other times lighting the lamps by alternatingcurrent at reduced voltage.

Another feature of my invention is the provision of means for continuingthe normal charging rate for a storage battery for signal control andemergency lighting while the lamps are being lighted by alternatingcurrent at reduced voltage.

Still another feature of my invention is the provision of means forlighting the lamps by alternating current at reduced voltage, or bydirect current, in the event of failure of the lighting controlapparatus.

I shall describe one form of apparatus embodying my invention, and shallthen point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view showing one form ofapparatus embodying my invention, in which a manually controllablearrangement is provided for supplying alternating current to a powertransmission line normally at a given voltage and at other times at areduced voltage, and in which a normally energized voltage reductionrelay becomes deenergized when the transmission line voltage is manuallyreduced, and a power-off relay becomes released when the transmisionline voltage is further reduced, such, for example, as by a failure ofthe alternating current source, and also in which signal lamps arelighted by current at normal voltage and a storage battery for signalcontrol and emergency lighting is charged at a normal rate when the vota e r duction relay is in it operated oondi- 2 tion, and the signallamps are lighted by current at reduced voltage and the storage batteryis still charged at the normal rate when the voltage reduction relay isreleased.

Similar reference characters refer to similar parts in the drawing.

Referring to the drawing, a stretch of single track railway is shownprovided with a plurality of signals including signals IS and 25 forgoverning traffic movements in opposite directions. The signals may beof any suitable design such, for example, as the color light type, eachof which has a green lamp G, a yellow lamp Y, and a red lamp R.

The stretch of railway track is divided by insulated joints 3 intosections, including sections a-b and bc, in a well-known arrangement.Each of these sections may be provided with a track circuit of anysuitable type including a source of current such as a battery 4connected across the rails adjacent one end of the section, and a trackrelay, designated by the reference character TR with a distinguishingprefix, connected across the rails adjacent the opposite end of thesection.

A pole-changer relay, designated by the reference character IPC, may becontrolled in a wellknown manner to be energized or deenergizedaccording to traffic conditions in advance of signal IS. A secondpole-changer relay 2P0 is similarly controlled according to trafficconditions in advance of signal 28.

The lighting of the G, Y and R lamps of each signal is controlled by asignal relay designated by the reference character H preceded by anumeral which is the same as the numeral in the reference character forits signal, each of which has a slow release neutral armature.

Each of the signal relays H may be controlled by a well-known circuitarrangement such, for example, as shown for relay IH, which includesfront contacts of track relays ITR, 2TB and AZTR, and pole-changingcontacts of relay IPC.

A power transmission line M, comprising conductors 5 and 6, is suppliedwith alternating current from the secondary winding d of a powertransformer P. Primary winding m of this transformer is provided withouter voltage terminals 9 and H, and with an intermediate voltageterminal l0. Energization of primary winding m of transformer P fromterminals BX and NX of a suitable source of alternating current iscontrolled by a power control relay W.

Energization of relay W may be controlled manually by any suitable meanssuch, for example, as by a control lever V which controls thetransmissionof carrier current over conductors l and 8 of a telephoneline L for effecting energization of relay W.

Current from a suitable source having terminals B and N, controlled bylever V, is supplied to an oscillator-amplifier A which in turn suppliescarrier current through a filer aF to telephone line L. This carriercurrent is fed from line L through a second filter bF to an amplifier,designated by the reference character AM, which in turn supplies currentfor energizing relay W.

Primary winding m of a lighting and battery charging transformer Kis-energized by current from power transmission line M. Transformer Khas a lighting secondary winding gal, and a battery charging secondarywinding ed.

A voltage reduction relay VB is energized by current from secondarywinding gd through asymmetric units in and 52. The parts of theapparatus are so proportioned that relay VB is in its operatedcondition, with its front contacts closed, while relay W is energized,and relay VR becomes released when relay W is deenergized.

A power-off relay PO is energized from secondary winding gd through atransformer 0K and a rectifier 00 which comprises asymmetric units 1 2',22, Si and 42'. Relay PO remains in the operated condition while relay Wis either energized or deenergized but relay PO becomes released whenthere is a further reduction in transmission line voltage such, forexample, as when there is a failure of the source which has terminals BXand NX.

While relay VB is energized, lighting current at normal voltage issupplied to the signal lamps. When relay VR becomes released, thelighting current voltage supplied by secondary winding gel oftransformer K also becomes reduced, and a resistor I9 is then includedin the lighting circuits for adjusting the reduced lighting voltage.

Secondary winding cd of transformer K is provided with outer voltageterminals I2 and I l and with an intermediate voltage terminal l3. Whilecurrent of normal voltage is supplied to transmission line M, relay VBis energized, so battery Q is charged at a normal rate from terminals 53and M of secondary winding cd of transformer K, through a rectifier 00which comprises asymmetric units li, 81', 82' and H12. While current atreduced voltage is supplied to transmission line M, relay VB isreleased. Battery Q is then charged at the same normal rate fromterminals l2 and M of secondary winding cd of transformer K.

Asymmetric units If to llli, inclusive may be of any suitable designsuch, for example, as the well-known half-wave copper oxide rectifierunits.

.The signal control circuits are energized at all times by current frombattery Q. When relay PO becomes deenergized, the signal lamps are alsolighted from battery Q. The voltage of the lighting current from batteryQ may be adjusted by means of a resistor 3|.

Having described, in general, the arrangement and control of the variousparts of apparatus embodying my invention, I shall now describe thecircuits and operation in detail.

As shown in the drawing, all parts of the apparatus are in the normalcondition, that is, the stretch of railway track shown is unoccupied,and so the track relays are energized; traffic conditions in advance ofsignals IS and 28 are such 4 that relays IPC and ZPC are energized bycurrent of normal polarity; relays lI-I and Eli are therefore energizedby current of normal polarity; lever V is in its normal or n position;relays W, VR and P0 are in their energized or operated condition; lampsG are energized by lighting current at normal voltage; and battery Q isbeing charged at a normal charging rate.

With lever V in its 11. position, oscillatoramplifier 0A is energized bycurrent from a suitable source having terminals B and N, throughcontacts l5 and It of lever V closed in the normal position.Oscillator-amplifier 0A in turn supplies carrier current of a givenfrequency through filter 041 to telephone line L. This carrier currentis supplied through a second filter bF to an amplifier AM which in turnenergizes relay W.

With relay W energized, primary winding m of transformer P is energizedby current passing from terminal BX. of the source of alternatingcurrent, through the front point of contact ll of relay W, terminal 9 ofprimary winding m, through primary winding m, and terminal ll of primarywinding m, to terminal NX of the same source of current. Current atnormal voltage is therefore supplied from secondary winding d oftransformer P to transmission line M. Primary winding m of transformer Kis therefore energized by current of normal voltage from transmissionline M, and hence relays VR and P0 are energized from secondary windingad of transformer K, and are in the operated condition.

With relays VR and PO energized, lamps G of signals is and ZS arelighted by current at normal voltage, passing from secondary winding adof transformer K, through contact !8 of relay VR in multiple withresistor l9, front point of contact 2!! of relay PO, then by twomultiple paths one of which includes lamp G of signal IS and contact 2!of relay IH in the normal position and also the front point of contact22 of relay HH, and the other one of the two multiple paths includinglamp G of signal ZS and contact 2| of relay 2H in the normal positionand also the front point of contact 22 of relay 2H, and then by a singlepath through the front point of contact 23 of relay PO, back tosecondary winding gel of transformer K.

With relay VR energized, a normal charging circuit for battery Q isclosed, which includes the front point of contact 24 of relay VR,terminals 13 and M of secondary winding cd of transformer K and theportion of Winding ad which is between.

terminals l3 and M, an impedance 25, and rectifier cC.

Relay lI-I is energized by a circuit passing from battery Q, through thefront point of contact 26 of relay IPC, contacts 21, 28 and 29 of relaysAZTR, 2TB. and ITR, respectively, winding of relay IE, and front pointof contact 39 of relay IPC back to battery Q. Relay 2H is energized by asimilar circuit.

I shall assume that, with apparatus arranged as shown in the drawing, itis decided to reduce the intensity of the light emitted by the signallamps. A leverman or dispatcher will therefore move lever V from itsnormal or 12 position to its reverse or 1' position, thereby openingcontacts l5 and iii of lever V and thus disconnecting terminals B and Nfrom oscillator-amplifier 0A.

Relay W, therefore, becomes deenergized, and hence its contact I! opensat the front point and becomes closed at the back point.

Primary winding 'm of transformer P is therefore now supplied withalternating current passing from terminal BX, through the back point ofcontact I! of relay W, terminal ID of primary winding m of transformerP, a portion of primary winding m, and terminal I I of this primarywinding, to terminal NX of the same source of current. Reducedalternating current voltage is therefore now applied by secondarywinding d of transformer P across conductors 5 and i of trans missionline M.

A reduced voltage is therefore now supplied through transmission line Mto primary winding m of transformer K, and hence relay VR becomesreleased, so that its front contacts open.

The signal lighting circuits now differ from the circuits previouslydescribed in that the shunt path around resistor l9 through contact ll!of relay VB is open. Alternating current at reduced voltage is thereforenow supplied to signal lamps G through resistor l9.

Battery Q is now charged at the normal charging rate by a circuit whichincludes the back point 24 of relay VR and all of secondary winding cdbetween terminals 12 and M of transformer K.

Relays lI-I and 2H are now energized by circults which are the same asthe circuits previously described for these relays.

I shall next assume that all parts of the apparatus are again in thenormal condition, and that the source of alternating current fails, orthat one of the line conductors of transmission line M breaks. Relay PO,as well as relay VB, will now release. Lamps G of the signals willtherefore now be lighted by a circuit passing from battery Q, throughthe back point of contact 23 of relay PO, then by the multiple pathspreviously described, and then through the back point of contact 20 ofrelay PO, and resistor 3! back to battery Q. Relays III and 2H are stillenergized by the circuits previously described for these relays.

I shall now assume that all parts of the apparatus are again in thenormal condition, and that there is a failure of the control apparatus,so that relay W becomes deenergized. Relay VR will therefore now releaseits front contacts as before, and the signal lamps will be lighted bycurrent at reduced voltage, as previously described. With relay VR,deenergized, battery Q is still charged at the normal rate, aspreviously described, and signal relays l H and 2H are still energized.

As has previously been described, when there is a failure of thealternating current source, so that relay PO is in its deenergizedcondition, lamps G may be lighted at a lower voltage if resistor 31 isadjusted to accomplish that result.

Although I have herein shown and described only one form of apparatusembodying my invention, it is understood that various changes andmodifications may be made therein within the scope of the appendedclaims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. A lighting control arrangement for railway signal lamps comprising,in combination, a power transmission line, a power transformer having asecondary winding connected across the conductors of said transmissionline and having a primary winding provided with two outer terminals andan intermediate terminal, a source of alternating current, manuallycontrollable means for at times connecting said source across said twoouter terminals and for at other times connecting said source acrosssaid intermediate terminal and one of said outer terminals, a batteryfor energizing control means for said signals, a lighting transformerhaving a primary winding connected across said transmission line andhaving a lighting secondary winding and a battery charging secondarywinding, a voltage reduction relay and a power-off relay energized bycurrent from said lighting secondary winding and arranged for saidvoltage reduction relay to release when said source is connected withsaid intermediate terminal and for said power-off relay to release whenthe voltage of said source is reduced still further below a givenmagnitude, means controlled by said voltage reduction relay when in itsoperated condition for lighting said signal lamps by alternating currentfrom said lighting secondary winding at a given voltage and for chargingsaid storage battery from a given portion of said charging secondarywinding at a normal rate, means controlled by said voltage reductionrelay in its released condition for lighting said signal lamps from saidlighting secondary winding through a resistor at a reduced voltage andfor charging said storage battery at said normal rate from more thansaid given portion of said charging secondary winding, and meanscontrolled by said power-01f relay in its released condition forlighting said signal lamps by current from said storage battery.

2. A lighting control arrangement comprising, in combination, a powertransmission line, a power transformer having a secondary windingconnected across the conductors of said transmission line and having aprimary winding provided with two outer voltage terminals and with anintermediate voltage terminal, a source of alternating current, manuallycontrollable means for at time connecting said source across said twoouter terminals and for at other times connecting said source acrosssaid intermediate terminal and one of said outer terminals, a lightingrelay controlled by current from said transmission line to be in anoperated or a released condition according as said source is connectedacross said two outer terminals or across said intermediate terminal andone of said outer terminals, and a lighting circuit controlled by afront contact of said lighting relay connected in multlple with aresistor for supplying lighting current at a given voltage when saidlighting relay is in its operated condition and for supplying lightingcurrent at a reduced voltage when said lighting relay is deenergized.

3. A lighting control arrangement comprising, in combination, a powertransmission line, a power transformer having a secondary windingconnected across the conductors of said trans-- mission line and havinga primary winding provided with two outer voltage terminals and with aintermediate voltage terminal, a source of alternating current, manuallycontrollable means for at times connecting said source across said twoouter terminals and for at other times connecting said source acrosssaid intermediate terminal and one of said outer terminals, a lightingrelay controlled by current from said transmission line to be in anoperated or a released condition according as said source is connectedacross said two outer terminals or across said intermediate terminal andone of said outer terminals, a lighting circuit controlled by saidlighting relay for supplying lighting current at a given voltage whensaid lighting relay is in its operated condition and for supplyinglighting current at a reduced voltage when said lighting relay isreleased, a storage battery, a battery charging transformer having aprimary winding energized from said transmission line, means controlledby said lighting relay in its operated condition for charging saidbattery at a given normal rate by energy from a given portion of asecondary wind ing of said transformer, means controlled by s lightingrelay in its released condition for charging said battery at said normalrate by energy from more than said given portion of said chargingsecondary winding, and'power-oif means for supplying lighting currentfrom said battery when said transmission line is deenergized.

4. A lighting control and battery charging ar rangement for railwaysignal lamps comprising, in combination, a power transmission line, apower transformer having a secondary winding connected across theconductors of said transmission line and having a primary winding, 21.source of alternating current, manually controllabie means for at timesconnecting said source across a first and a second portion of saidprimary winding in series and for at other times connecting said sourceacros only said first portion, a lighting transformer having a primarywinding ccnn cted across said transmission line and having a ingsecondary winding and a battery cha secondary winding, a voltagereduction relay ell ergized from said lighting secondary winding andproportioned to be operated for closing a front contact when said sourceisconnected across said two portions of the primary winding of saidtransformer but to be released for closing a bacl: contact when saidsource is connected across only said first portion of said primarywinding, a stor age battery, a charging circuit for said storage batteryincluding a first and a second portion of said battery charging secondarwinding in series and controlled by said back contact of said voltagereduction relay, a second charging circuit for said storage batteryincluding only said first por tion of said battery charging secondarywinding and controlled by said front contact or said voltage reductionrelay, a lighting circuit for lighting said signal lamps by current fromsaid lighting secondary winding at a given voltage or at areduced'voltage according as said source is connected across said bothportions or only said first portion respectively of said primary windingof said power transformer, and a circuit responsive to deenergization ofsaid power transmission line for lighting said signal lamps by currentfrom said battery.

5. A lighting control and battery charging arrangement for railwaysignal lamps comprising, in combination, a power transmission line,manually controllable means for at times supplying alternating currentat a given voltage to said transmission line and for at other timessupplying alternating current at a reduced voltage to said transmissionline, a transformer having a primary winding connected acros saidtransmission line and having a battery charging secondary windingcomprising a first part and a second part and also having a lightingsecondary winding, a charging relay energized by current from saidlighting secondary winding and proportioned to close a front contact ifsaid transmission line is energized at said given voltage but to close aback contact if said transmission line is energized at said reducedvoltage or is deenergized, a storage battery, a charging circuit forsaid battery controlled by said front contact and including only saidfirst part of said battery charging winding, a second charging circuitfor said battery controlled by said back contact and including saidfirst and second parts of said battery charging winding in series,lighting circuit means including said lighting secondary windin forenergizing said signal lamps to have a given light intensity if saidtransmission line is energized at said given voltage but energizing saidsignal lamps to have a reduced light inten sity if said transmissionline is energized at said reduced voltage, and other lighting circuitmeans responsive to deenergization of said transmission line forenergizing said signal lamps from said storage battery.

6. A lighting control and battery charging arrangement for railwaysignal lamps comprising, in combination, a power transmission line, manually controllable means {for at times supplying alternating current ata given voltage to said transmission line and for at other timessup-plying alternating current at a reduced voltage to said transmissionline, a transformer having a primary winding connected across saidtransmission line, a storage battery, means responsive to energizationof said transmission line at said given voltage including a givenportion of a secondary winding of said transformer and also at saidreduced voltage including more than said given portion of said secondarywinding of said transformer for charging said storage battery at a givenrate, lighting circuit means for energizing said signal lamps from saidtransformer to have a given light intensity or a reduced light intensityaccording as said transmission line energized at said given voltage orat said reduced voltage, and other lighting circuit means responsive todeenergization of said transmission line for energizing said signallamps from said storage battery.

RALPH R. KEMMERER.

No references cited.

